Electric heating



Feb. 15, 1949. A. P. WBEGAND 294629015 ELECTRIC HEATING Filed April 3, 1947 ALEEFFT F. W/EE'A/VD JNVEA/TUE,

Patented Feb. 15, 1949 ELECTRIC HEATING Albert P. Wiegand, Pittsburgh, Pa., assignor to Edwin L. Wi

egand Company.

Pittsburgh, Pa.,

a corporation of Pennsylvania Application April 3, 1947, Serial No. 739,156

11 Claims.

My invention relates to electric heating, and to tubular sheathed embedded-resistor electric heating elements, and to electric heating units comprising one or more such elements, and the principal object of my invention is the production of new and improved elements and units of the type indicated.

In the drawing accompanying this specification and forming a part of this application I have shown for purposes of illustration one form which my invention may assume, and in this drawing:

Figure 1 is a top plan View of a range unit embodying my invention,

Figure 2 is a cross-sectional view showing the element in an original circular cross-section, and

Figure 3 is a cross-sectional view on the line 33 of Figure 1.

In the drawing I have shown a range unit i0 comprising a ring II by which the unit maybe supported from the top of an electric range, a spider l2 mounted in the ring II and carrying centrally a medallion l3, and two electric heating elements It supported on the spider I2, having their end portions l5 extending to a terminal block sheath H, a resistor I8 disposed within the sheath l1, and compacted granular refractory l9 embedding the resistor IB and serving to insulate the resistor and to conduct the heat from the resistor to the sheath.

In the illustrated embodiment of my invention each of the heating elements I4 is originally constructed circular in cross-section, as shown in Figure 2, and then preferably the entire active portion of the element is side pressed to the crosssection shown particularly in Figure 3, as by means of coacting dies 20 and 2|, the die 20 being provided with a groove or channel 22 in which the element is disposed, the die 2| being substantially flat, and the operation comprising relative approach of the dies to substantially the position indicated in Figure 3, whereby the included section of the element is formed generally to the contour of the die cavity, but with lateral projections 23 substantially extending the area of the corresponding element surface 24.

As appears from Figures 2 and 3, the final cross-section shown in Figure 3 is substantially less than the initial cross-section shown in Figure 2, whereby the refractory I9 is firmly and but inasmuch as the dies 20 and 2! are notsbrought together, the operation avoids the likelihood of pinching and splitting the heath, and permits the formation to final cross-section in a, single operation.

[6, and each comprising a tubular Further, when the elements are used in a range unit, as shown in Figure 1, the provisions of the lateral projections 23, and the increased width of the upper face 24, afford the very important advantage of a substantial increase in the area, of contact between the elements and the pan or other culinary utensil positioned thereon, thus transfer of the heat from the elements to the utensil, permitting higher watt density in the elements, and resulting in substantially increased cooking speed.

From the foregoing it will be understood by those skilled in the art that the illustrated embodiment of my invention provides a new and improved electric heating element and method of making the same, and a new and improved heating unit, and therefore accomplishes at least the principal object of my invention, and also it will be understood that the particular embodiment of my invention herein shown and described is illustrative only, and that various changes and modifications may be made, within the scope of my invention, and accordingly that my invention is not limited to the particular illustrated embodiment.

Wherefore I claim:

1. A tubular sheathed embedded-resistor electric heating element having an active section comprising a tubular sheath formed to a cross section consisting substantially of two wall sections disposed in approximately V-relation and having their adjacent edges closed to each other and a complementary wall section generally inverted channel shape in cross-section and having its base extending laterally beyond the separate edges of said two wall sections and its sides continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compacted granular refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat from said resistor means to said sheath.

2. A tubular sheathed embedded-resistor electric heating element having a curvilinear active section comprising a tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximately V-lelation and having their adjacent edges closed to each other and a complementary wall section generally inverted channel shape in cross-section having its base portion extending laterally beyond the separate edges of said two wall sections and its side portions continued inwardly and respectively closed to said separate edges, resistor means disinverted channel shape posed in said sheath, and compacted granular refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat from said resistor means to said sheath.

3. A tubular sheathed embedded-resistor electric heating element having a curvilinear active section disposed in a formation defining a surface and comprisinga tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximatelyV-relation and having their adjacent edges closed to each other and a complementary wall section generally inverted channel shape in cross-section having its base extending laterally beyond the separate edges of said two wallsections and disposed substantially in said surface and its sides continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compacted granular refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat from said resistor means to said sheath.

4. A tubular sheathed embedded-resistor electric heating element having a curvilinear active section disposed in a formation defining a plane and comprising a tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximately V-relation and having their adjacent edges closed toeach other and a complementary wall section generally inverted channel shape in cross-sectionhaving its base extending laterally beyond the separate edges of said two wall sections and disposed sub stantially in said plane and its sides continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compacted granular. refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat from said resistor means to said sheath.

5. A tubular sheathed embedded-resistor electric heating element having a curvilinear active section disposed in a formation defining a surface and comprising a tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximately V-relation and having their adjacent edges closed to each other and a complementary wall section generally in cross-section havin its base extending laterally beyond the separate edges of said two wall sections and disposed substantially in said surface and its sides continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compacted granular refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat from said resistor means to said sheath, said element comprising also terminal portions, and said terminal portions each extending away from said surface.

6. A tubular sheathed embedded-resistor electric heating element' having a curvilinear active section disposed in a formation defining a plane and comprising a tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximately V-relation and having their adjacent edges closed to each other and a complementary wall section generally inverted channel shape in cross-section having its base extending laterally beyond the separporting defining a surface and ate edges of said two wall sections and disposed substantially in said plane and its sides continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compacted granular refractoryv material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat from said'resistor means to said sheath, said element comprising also terminal portions, and said terminal portions each extending away from said plane. Y

7. An electric heating unit comprising supporting means and-a tubular sheathed embeddedresistor electric heating element carried by said supporting means, said element having a curvilinear active section disposed in a formation comprising a tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximately V-relation and having their adjacent edges closed to each other and a complementary wall section generally inverted channel shape in cross-section having its base extending laterally beyond the separate edges of said two wall sections and disposed substantially in said surface and its side portions continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compactedgranular refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat from said resistor means linear active section disposed in a formation defining a plane and comprising a tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximately V-relation and having their adjacent edges closed to each other and a complementary wall section generally inverted channel shape in cross-section having its base extending laterally beyond the separata edges of said two wall sections and disposed substantially in said plane and its sides continued inwardly and respectively closed to saidseparate edges, resistor means disposed in said sheath, and compacted granular refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate saidresistor means and to conduct the heat from said resistor means to said sheath.

9. An electricheating unit comprising 'sup means and a tubular sheathed embedded-resistor electric heating element carried by said supporting means, said element having a curvilinear active section disposed in a form-ation defining a surface and comprising a tubular sheath formed to a cross-section consisting substantially of two .wall sections disposed in approximately V-relation and having their adjacent edges closed to each other and a complementary wall section generally, inverted channel shape in cross-section having its base extending laterally beyond the separate edges of said two wall sections and disposed substantially in said surface and its sides continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compacted granular refractory material disposed in said sheath embedding said resistor means and serving to electrically insulate said resistor means and to conduct the heat; from said resistor means to said sheath, said element comprising alsc terminal portions, and said terminal portions each extending away from said surface.

10. An-electric heating unit comprising supporting means and a tubular sheathed embeddedresistor electric heating element carried by said supporting means, said element having a curvilinear active section disposed in a formation defining a plane and comprising a tubular sheath formed to a cross-section consisting substantially of two wall sections disposed in approximately V-relation and having their adjacent edges closed to each other and a complementary wall section generally inverted channel shape in cross-section having its base extending laterally beyond the separate edges of said two wall sections and disposed substantially in said plane and its sides continued inwardly and respectively closed to said separate edges, resistor means disposed in said sheath, and compactedgranular refractory material disposed in said sheath embedding said resistor means and to conduct the heat from said resistor means to said sheath, said element comprising also terminal portions, and said terminal portions each extending away from said plane.

11. The process of making a tubular sheathed embedded-resistor electric heating element having an active section in which the refractory is highly compacted, which comprises constructing said element and then pressing said active secion between a grooved die and a complementary die and forcing the sheath to flow laterally beyond the edges of the grooving forming said active section to a cross-section corresponding to the die cavity but comprising lateral extensions extending the surface of the sheath.

ALBERT P. WIEGAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

